"A lot of people associate him with Malcolm Tucker who's very grumpy, but that could work for the Doctor," Gillan added.

Capaldi will make his first appearance on the show at Christmas when viewers bid farewell to Smith's incarnation of the Time Lord.

Doctor Who will return to screens for its 50th anniversary special 'The Day of the Doctor' on November 23. The episode will air simultaneously worldwide and stars Matt Smith, David Tennant, John Hurt, Billie Piper and Jenna Coleman.